JP6995019B2 - Sample holder - Google Patents

Description

The present disclosure relates to a sample holder used for holding each sample such as a semiconductor wafer in a manufacturing process of a semiconductor integrated circuit or the like.

As sample holders used in semiconductor manufacturing equipment, for example, it corresponds to a plate-shaped ceramic substrate having a heating surface on which a substrate is placed on one surface, and each zone obtained by dividing the heating surface into a plurality of zones. Multiple resistance heating elements with independent input / output terminals embedded in the ceramic substrate, and multiple drawers connected to each input / output terminal and wired along the outer surface other than the heating surface of the ceramic substrate. A substrate heating device having a wire (conduction portion) is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-303014

Here, in order to suppress the deterioration of the soaking property of the sample holding surface due to the heat generation of the conductive portion, it is conceivable to form the conductive portion with a conductor having a plate-shaped portion instead of a linear portion. However, in such a configuration, when a temperature cycle is applied, there is a problem that the thermal expansion difference generated between the conductive portion and the member adjacent to the conductive portion causes peeling and the durability is lowered. ..

The present disclosure has been made in view of the above circumstances, and an object of the present invention is to provide a sample holder that is less likely to be peeled off between a conductive portion and a member adjacent to the conductive portion and has improved durability.

The sample holder of the present disclosure includes a ceramic substrate whose main surface is a sample holding surface, a heat generating resistor provided inside or on the other main surface of the ceramic substrate, and the other main surface of the ceramic substrate. A metal member having a through hole opened in a first surface and a second surface located opposite to the first surface, and a lead inserted into the metal member. The terminal is provided inside the bonding layer and includes a conductive portion that electrically connects the heat generating resistor and the lead terminal, and the conductive portion is the other of the ceramic substrate. It has a plate-shaped portion that is located away from the main surface and is located opposite to the other main surface of the ceramic substrate, and a film-like member that covers the plate-shaped portion. It is characterized by having a recess on the surface.

According to the sample holder of the present disclosure, a part of the bonding layer enters the recesses of the film-like member constituting the conductive portion, and peeling is less likely to occur between them, so that the durability is improved.

It is sectional drawing which shows an example of a sample holder. FIG. 3 is an enlarged cross-sectional view taken along the width direction as an example of the conductive portion of the sample holder shown in FIG. FIG. 3 is an enlarged plan view of another example of the conductive portion of the sample holder shown in FIG. 1. FIG. 3 is an enlarged plan view of another example of the conductive portion of the sample holder shown in FIG. 1. FIG. 3 is an enlarged plan view of another example of the conductive portion of the sample holder shown in FIG. 1. It is a plane perspective view explaining the arrangement example of the conduction part of a sample holder. FIG. 3 is an enlarged plan view of another example of the conductive portion of the sample holder shown in FIG. 1.

Hereinafter, embodiments of the sample holder 10 will be described with reference to the drawings.

As shown in FIG. 1, the sample holder 10 includes a ceramic substrate 1 having a sample holding surface 11 on one main surface. The ceramic substrate 1 has, for example, a circular outer peripheral shape when viewed in a plan view, and is formed in a disk shape having a diameter similar to that of the object to be held. The ceramic substrate 1 has a sample holding surface 11 for holding a sample to be held on one main surface (upper surface). As the material of the ceramic substrate 1, an alumina, sapphire, an alumina-titania composite material, an oxide-based ceramic such as barium titanate, or a nitride-based ceramic such as aluminum nitride can be used. The dimensions of the ceramic substrate 1 can be set, for example, to have a diameter of 200 mm to 500 mm and a thickness of 2 mm to 15 mm.

Here, the sample holder 10 holds an object (sample) to be held such as a silicon wafer, and is, for example, an electrostatic chuck. At this time, the ceramic substrate 1 has an electrostatic adsorption electrode inside. The electrostatic adsorption electrode has a material such as platinum or tungsten. A lead wire is connected to the electrostatic adsorption electrode. The electrostatic adsorption electrode is connected to the power supply via this lead wire. On the other hand, the object to be held that is adsorbed on the sample holding surface 11 is connected to the ground. As a result, an electrostatic adsorption force is generated between the electrostatic adsorption electrode and the object to be held (sample), and the object to be held (sample) can be adsorbed and fixed to the sample holding surface 11.

A heat generation resistor 2 is provided inside or on the other main surface of the ceramic substrate 1. In the sample holder 10 of the form shown in FIG. 1, the heat generation resistor 2 is provided on the other main surface (lower surface) of the ceramic substrate 1.

The heat generation resistor 2 is a member for heating the sample held on the sample holding surface 11 on the upper surface of the ceramic substrate 1. The heat generation resistor 2 is electrically connected to the lead terminal 5 through a conduction portion 6 to be described later, and the heat generation resistor 2 can be heated by passing a current through the lead terminal 5. .. The heat generated by the heat generation resistor 2 travels inside the ceramic substrate 1 and reaches the sample holding surface 11. As a result, the sample held on the sample holding surface 11 can be heated.

The heat generation resistor 2 is a linear pattern having a plurality of folded portions, and is provided on almost the entire surface of the other main surface (lower surface) of the ceramic substrate 1. Further, the heat generation resistor 2 has a pattern shape optimally designed to improve the heat soaking property. The dimensions of the heat generation resistor 2 are designed according to the required resistance and electric energy, and for example, the width of the heat generation resistor 2 is set to 0.1 mm to 10 mm, the thickness is set to 10 μm to 5 mm, and the length is set to 50 mm to 5 m.

This makes it possible to prevent variations in heat distribution on one main surface (upper surface) of the sample holder 10.

The heat generation resistor 2 contains conductor components such as silver, palladium, platinum, aluminum, and gold. Further, the heat generation resistor 2 may contain a glass component. Examples of the glass component include oxides of materials such as silicon, aluminum, bismuth, calcium, boron and zinc. When the heat generation resistor 2 is provided inside the ceramic substrate 1, the conductor component may be tungsten, tungsten carbide, or the like.

Here, the following method can be used to control the temperature of the sample holder 10. Specifically, the temperature can be measured by bringing the thermocouple into contact with the ceramic substrate 1. Further, the temperature of the heat generating resistor 2 can also be measured by contacting the resistance temperature detector 1 with the ceramic substrate 1 and measuring the resistance. By adjusting the voltage applied to the heat generation resistor 2 based on the temperature of the heat generation resistor 2 measured as described above, the heat generation of the heat generation resistor 2 is generated so that the temperature of the sample holder 10 becomes constant. Can be controlled.

A metal member 3 is provided so as to cover the other main surface of the ceramic substrate 1. The metal member 3 has a through hole 31 that opens into one main surface and the other main surface.

The metal member 3 is provided to support the ceramic substrate 1. The metal member 3 covers the other main surface so that one main surface (upper surface) faces the other main surface (lower surface) of the ceramic substrate 1. Specifically, the other main surface (lower surface) of the ceramic substrate 1 and the upper surface of one main surface (upper surface) of the metal member 3 are joined by the joining layer 4. The "metal" of the metal member 3 referred to here includes a composite material of ceramics and metal, a composite material made of a fiber-reinforced metal, and the like. Generally, when the sample holder 10 is used in an environment exposed to a halogen-based corrosive gas or the like, the metal constituting the metal member 3 may be aluminum (Al), copper (Cu), stainless steel or the like. Nickel (Ni) or alloys of these metals can be used.

For example, the metal member 3 has a circular outer peripheral shape when viewed in a plan view, and is formed in a disk shape having a diameter similar to that of the ceramic substrate 1. The metal member 3 has a thickness of, for example, 10 mm to 100 mm. Further, the metal member 3 has a through hole 31 that opens in one main surface (upper surface) and the other main surface (lower surface), and a lead terminal 5 is provided so as to pass through the inside of the through hole 31. Has been done. In other words, the lead terminal 5 is inserted into the metal member 3. The shape of the through hole 31 is, for example, a shape in which the internal space is cylindrical. The diameter of the through hole 31 can be set to, for example, 0.1 mm to 10 mm.

One end of the lead terminal 5 is connected to the conductive portion 6, and the other end is connected to an external power supply (not shown). As the lead terminal 5, for example, a metal material having electrical conductivity such as nickel can be used. The lead terminal 5 and the conductive portion 6 can be connected by using, for example, solder, a brazing material, or the like having electrical conductivity.

The metal member 3 may be provided with a flow path for circulating a heat medium such as a gas or a liquid. In this case, a liquid such as water or silicone oil or a gas such as helium (He) or nitrogen (N ₂ ) can be used as the heat medium.

A bonding layer 4 for adhering these is provided between the other main surface of the ceramic substrate 1 and one main surface of the metal member 3. In other words, the other main surface (lower surface) of the ceramic substrate 1 and one main surface (upper surface) of the metal member 3 are bonded by the bonding layer 4.

The bonding layer 4 has a polymer material. As the polymer material, for example, it has an epoxy resin and a silicone resin. The bonding layer 4 may have a filler dispersed in the polymer material in addition to the polymer material. As the filler, for example, ceramic particles can be used. As the ceramic particles, for example, alumina, aluminum nitride, or the like can be used.

The thickness of the bonding layer 4 can be set to, for example, 0.05 mm to 2.0 mm. Here, the sample holder 10 may have a through hole penetrating from the upper surface of the ceramic substrate 1 to the lower surface of the metal member 3 through the bonding layer 4.

The sample holder 10 includes a conductive portion 6 provided inside the bonding layer 4. The conductive portion 6 is made of a metal material having electrical conductivity such as copper and aluminum. The conduction portion 6 electrically connects the heat generation resistor 2 and the lead terminal 5, one end of which is connected to the heat generation resistor 2 and the other end of which is connected to the lead terminal 5. The conductive portion 6 is a plate located away from the other main surface (lower surface) of the ceramic substrate 1 and extending in a direction along the other main surface and facing the other main surface. It has a shaped portion 61 and a film-shaped member 62 that covers the plate-shaped portion 61. Further, the conductive portion 6 also has a portion 63 extending in the vertical direction. As the plate-shaped portion 61 of the conductive portion 6, for example, a metal plate, a metal foil, or the like can be used. Further, the portion 63 of the conductive portion 6 extending in the vertical direction electrically connects the heat generating resistor 2 and the plate-shaped portion 61, and for example, a via hole conductor, a metal foil, or the like can be used.

As shown in FIG. 2, the film-like member 62 is provided so as to cover the surface of all the regions extending in the direction along the other main surface, except for the joint portion with the lead terminal 5 in the plate-shaped portion 61, for example. .. The film-like member 62 does not have to cover the portion 63 extending in the vertical direction of the conductive portion 6. Examples of the material for forming the film-like member 62 include a film made of a resin such as polyimide or a fluorine-based resin. The thickness of the film-like member 62 (thickness of the portion other than the recess 621) is set to, for example, 30 μm to 100 μm.

By providing the film-like member 62, the effect of ensuring the insulating property between the heat generation resistor 2 and the conductive portion 6 can be obtained.

Here, the film-like member 62 may be provided via an adhesive such as an epoxy resin, and in this case, the adhesive also constitutes a part of the film-like member 62.

The material of the film-like member 62 is preferably one having a thermal conductivity close to that of the bonding layer 4, and may be the same as the material of the bonding layer 4.

Then, as shown in FIG. 2, the film-like member 62 has a recess 621 on the surface thereof. The depth of the recess 621 is set to, for example, 1 μm to 20 μm. Examples of the recess 621 include a groove extending in the width direction of the conductive portion 6 as shown in FIG. 3 or a groove extending in the length direction of the conductive portion 6 as shown in FIG. When the recess 621 is a groove, the width of the groove when viewed in a plan view is set to, for example, 10 μm to 100 μm.

By providing such a recess 621 on the surface of the film-like member 62, a part of the bonding layer 4 enters the recess 621 and peeling is less likely to occur between them, so that the durability is improved.

Further, the recess 621 may be a grid-shaped recess 621 (a groove that becomes a grid when viewed in a plan view) as shown in FIG. By providing the lattice-shaped recesses 621 on the surface of the film-like member 62, a part of the bonding layer 4 alternately enters the lattice-shaped recesses 621, and the thickness of the bonding layer 4 changes alternately, so that heat drawing also alternates. There are good and bad points. Therefore, it is possible to suppress partial heat generation and excessive cooling, and it is possible to disperse the thermal stress, so that the heat soaking property is improved and the durability is improved.

Further, as shown in FIG. 6, if the conductive portion 6 is the first conductive portion 6, the second conductive portion 7 provided inside the joint layer 4 may be further provided. Here, when the plate-shaped portion 61 of the first conducting portion 6 is the first plate-shaped portion 61, the film-shaped member 62 is the first film-shaped member 62, and the recess 621 is the first recess 621, the second conduction portion 7 is used. Is a second plate-shaped portion 71 located away from the other main surface (lower surface) of the ceramic substrate 1 and facing the other main surface, and a second film-shaped portion covering the second plate-shaped portion 71. It has a member 72, and the second film-like member 72 may have a grid-like second recess 721 on the surface.

Further, as shown in FIG. 7, the direction in which the first recess 621 extends may be inclined with respect to the direction in which the second recess 721 extends. Specifically, the second recess 721 extending in the width direction of the second conducting portion 7 is tilted in the range of, for example, 10 degrees to 80 degrees with respect to the first recess 621 extending in the width direction of the first conducting portion 6. May be good. Similarly, the second recess 721 extending in the length direction of the second conducting portion 7 is tilted in the range of, for example, 10 degrees to 80 degrees with respect to the first recess 621 extending in the length direction of the first conducting portion 6. May be good. In other words, for example, when the length direction of the first conducting portion 6 (X1 direction) and the extending direction of the lattice-shaped first recess 621 (X2 direction) coincide with each other (when the inclination is 0 degrees), the first 2 The extending direction (X4 direction) of the lattice-shaped second recess 721 may be inclined in the range of 10 to 80 degrees with respect to the length direction (X3 direction) of the conductive portion 7.

By changing the direction of the grid-shaped recesses for each conductive part, the thermal stress due to the difference in thermal expansion between the conductive part and the joint layer is dispersed without being concentrated in a specific direction, making it more difficult to peel off and improving durability. ..

Hereinafter, a method for manufacturing the sample holder 10 will be described. Although alumina ceramics will be described as an example, other ceramic materials such as aluminum nitride ceramics can be produced by the same method.

First, a predetermined amount of alumina powder as a main raw material is weighed, and a 24-72 Hr wet pulverizing mixture is carried out in a ball mill together with ion-exchanged water, an organic solvent or the like or an organic dispersant and a ball made of metal or ceramics.

A predetermined amount of an organic binder such as polyvinyl alcohol, polyvinyl butyral or acrylic resin and a plasticizer and an antifoaming agent as auxiliary organic materials are added to the raw material slurry pulverized and mixed in this manner, and further mixed for 24 to 48 hours. The mixed organic-inorganic mixed slurry is formed into a ceramic green sheet by a doctor blade method, a calendar roll method, a press molding method, an extrusion molding method, or the like.

Then, a paste-like electrode material such as platinum or tungsten for molding the electrostatic adsorption electrode is printed and molded by a known screen printing method or the like. Further, 3 to 10 ceramic green sheets are laminated, and a hole for embedding a via hole conductor having a diameter of 0.1 mm to 0.8 mm is provided with a drilling machine or the like. A paste-like electrode material is embedded in the hole to form a via hole conductor. Further, a first conductor pattern having a diameter of 1 mm to 2 mm and a thickness of 20 μm to 30 μm is printed and molded directly under the via hole conductor. Further, a second conductor pattern having a diameter of 5 mm to 15 mm and a diameter of 20 μm to 30 μm is printed and molded from above the first conductor pattern formed by the printing.

Here, the ceramic green sheet obtained by molding the first conductor pattern and the second conductor pattern, the ceramic green sheet laminate in which the via hole conductor is embedded, and the green sheet in which the paste-like electrode material is not printed and molded are laminated. do. At the time of laminating, the ceramic green sheet may be laminated at a predetermined temperature while applying a pressure equal to or higher than the yield stress value of the ceramic green sheet. As the pressure application method, a known technique such as a uniaxial pressing method or an isotropic pressurizing method (dry method, wet method) may be applied.

Next, the obtained laminate is fired at a predetermined temperature in an atmosphere to produce a ceramic substrate 1 in which an electrostatic adsorption electrode is embedded.

Next, the ceramic substrate 1 is machined into a predetermined shape and thickness using a machining center, a rotary processing machine, or a cylindrical grinding machine.

Further, the heat generation resistor 2 is provided inside or on the back surface (the other main surface) of the ceramic substrate 1. The heat generation resistor 2 is a member for heating an object to be heated by generating Joule heat generation by energizing an electric current. When the heat generation resistor 2 is provided inside the ceramic substrate 1, it is formed by the same method as the electrostatic adsorption electrode. When the heat generation resistor 2 is provided on the back surface of the ceramic substrate 1, the heat generation resistor 2 preferably contains a conductor component and a glass component. The conductor component includes, for example, a metal material such as silver-palladium, platinum, aluminum or gold. In order to prevent the glass component from foaming, a metal that can be sintered in the atmosphere may be selected as the metal material. Further, the glass component contains oxides of materials such as silicon, aluminum, bismuth, calcium, boron and zinc. The heat generation resistor is linear and has a pattern shape optimally designed to improve heat soaking. The dimensions are designed according to the required resistance and electric energy, and for example, the width is set to 0.1 to 10 mm, the thickness is set to 10 μm to 5 mm, and the length is set to 50 mm to 5 m.

Further, the heat generation resistor 2 is provided inside or on the back surface (the other main surface) of the ceramic substrate 1. The heat generation resistor 2 is a member for heating an object to be heated by generating Joule heat generation by energizing an electric current. When the heat generation resistor 2 is provided inside the ceramic substrate 1, it is formed by the same method as the electrostatic adsorption electrode. When the heat generation resistor 2 is provided on the back surface of the ceramic substrate 1, the heat generation resistor 2 preferably contains a conductor component and a glass component. The conductor component includes, for example, a metal material such as silver-palladium, platinum, aluminum or gold. In order to prevent the glass component from foaming, a metal that can be sintered in the atmosphere may be selected as the metal material. Further, the glass component contains oxides of materials such as silicon, aluminum, bismuth, calcium, boron and zinc.

Next, a recess for feeding is provided on the back surface (the other main surface) of the ceramic substrate, which is different from the sample holding surface 11, so that a part of the electrostatic adsorption electrode is exposed at a machining center or a drilling machine.

Further, the metal member 3 made of aluminum or the like and the ceramic substrate 1 are joined. When the heat generation resistor 2 is provided on the back surface of the ceramic substrate 1, an epoxy paste is applied to the back surface of the ceramic substrate 1 and the excess paste is removed with a squeegee or the like and cured. Here, the feeding portions at both ends of the heat generation resistor 2 are sealed so that the paste does not adhere to the feeding portions. Next, it is processed with good flatness by rotary processing or the like to form the first layer of the bonding layer 4.

Next, a conductive portion 6 made of, for example, a metal foil such as copper or aluminum is arranged on the first layer of the bonding layer 4. The conductive portion 6 is connected to the heat generating resistor 2 at a portion 63 extending in the vertical direction by soldering or the like. Further, in the portion along the lower surface of the ceramic substrate 1, the lead terminal 5 is routed to a connectable region. The portion of the conductive portion 6 along the lower surface of the ceramic substrate 1 is exposed on the bottom surface of the recess. In other words, the other end of the conductive portion 6 is exposed on the bottom surface of the recess. Then, the other end is joined to the lead terminal 5 with solder or the like.

Here, the conductive portion 6 includes a plate-shaped portion 61 and a film-shaped member 62. An epoxy adhesive is applied to the surface of the film-shaped member 62, and the coated surface is wound around the plate-shaped portion 61 so as to be in contact with the surface of the plate-shaped portion 61. At this time, the conductive portion 6 and the lead terminal 5 are solder-bonded, and this solder-bonded portion is also coated with a silicone resin. At this time, the concave portion 621 can be formed on the surface of the film-like member 62 by curing the epoxy adhesive while pressing, for example, a fibrous wire or a cloth or mesh woven in a lattice pattern against the surface of the film-like member 62. .. At this time, the film-like member 62 includes the adhesive.

Next, a silicone paste is applied to the metal member 3, excess paste is removed with a squeegee or the like, the ceramic substrate 1 is adhered to the metal member 3 in a vacuum, pressed to a predetermined thickness, and heated to 100 ° C.
Allow to cure for 2 hours. The adhesive to be the bonding layer 4 may be cured at room temperature by adding a catalyst or the like. At this time, the end portion of the conductive portion 6 is aligned and adhered to the through hole 31 provided in the metal member 3 so as to be positioned.

Then, the lead terminal 5 for feeding is inserted into the through hole 31, the lead terminal 5 for the heat generating resistor 2 is inserted into the end of the conductive portion 6, and the lead terminal 5 is joined by soldering or the like.

Next, the thickness of the ceramic substrate 1 is finished to a predetermined thickness by rotary processing, lapping, or the like. At this time, a blast mask may be attached or formed on the suction surface, and a sealing portion and a convex portion may be formed by blasting.

In this way, the sample holder 10 of the present embodiment can be manufactured.

1: Ceramic substrate 2: Heat generation resistor 3: Metal member 31: Through hole 4: Bonding layer 5: Lead terminal 6: Conducting part (first conducting part)
61: Plate-shaped part (first plate-shaped part)
62: Membrane-like member (first film-like member)
621: Recess (first recess)
63: Vertically extending portion 7: Second conductive portion 71: Second plate-shaped portion 72: Second film-shaped member 721: Second concave portion

Claims (3)

A ceramic substrate whose main surface is a sample holding surface, a heat-generating resistor provided inside the ceramic substrate or on the other main surface, and a bonding layer so as to cover the other main surface of the ceramic substrate are interposed. A metal member having a through hole that opens in a first surface and a second surface located opposite to the first surface, a lead terminal inserted into the metal member, and the inside of the bonding layer. It is provided in the above, and is provided with a conduction portion for electrically connecting the heat generation resistor and the lead terminal.
The conductive portion is a plate-shaped portion located away from the other main surface of the ceramic substrate and facing the other main surface of the ceramic substrate, and a film-like member covering the plate-shaped portion. And have
The film-like member is a sample holder characterized by having a recess on the surface. The sample holder according to claim 1, wherein the recesses have a grid pattern. When the conductive portion is the first conductive portion, the plate-shaped portion is the first plate-shaped portion, the membrane-like member is the first film-like member, and the recess is the first recess.
Further, a second conduction portion provided inside the joint layer is provided.
The second conductive portion has a second plate-shaped portion located away from the other main surface of the ceramic substrate and facing the other main surface of the ceramic substrate, and the second plate-shaped portion. It has a second film-like member that covers the portion, and has a second film-like member.
The second film-like member has a grid-like second recess on the surface and has a lattice-like second recess.
The sample holder according to claim 2, wherein the direction in which the first recess extends is inclined with respect to the direction in which the second recess extends.

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